While using the mod wheel to try to control filter cutoff from one of the AUXs, I encountered an alarming amount of zipper noise. I got this from using the mod wheel on my Nord Stage, the bender on the D-50 and from drawing envelopes in my DAW.

I emailed Kenton support and as expected, they basically blamed the low resolution of midi CCs. They also told me there's no work around and they have no plans to update the Pro 2000 at any time soon or address this problem.

This is a huge disappointment because I had wanted to use midi envelopes and controls to create repeatable modulations for multi-tracking and for controlling a number of modules via mults with aftertouch or the mod wheel. I had also wanted to use programs like cableguys midishaper to create envelopes to use for modulations.

I'm not that familiar with how it all works but it seems that modern products have found workarounds to the limited resolution of 7 bit midi messages, for example using 14 bit NRPN messages.

Are there any possible solutions or workarounds you guys can come up with? Is there anything I should suggest to Kenton to help them bring their products into the 21st century? Is it possible to receive 7 bit midi CC messages and then interpolate the missing values and smooth the movement using NRPN messages to feed the CV output on the Kenton?

Obviously this is also a warning to those who were thinking of using Kenton Midi to CV products. I really wish I had known about this in advance because being able to use midi messages to control CV values was a big selling point for me.

Are there any midi to CV products that don't suffer from this handicap? Anyone use the SEM pro? Does the SEM pro's filter operate smoothly when using the mod wheel to open and close?

Any suggestions or workarounds are very welcome. Plus any tech knowledge for me to pass to Kenton in a reply to try to get them to fix this.

I've attached an audio sample of me opening and closing the VCF on my Patch Panel SEM using the Mod wheel and the Kenton Pro 2000 to generate the CV.

There is going to be audible stepping since 127 steps isn't much over such a broad range of volts, hence why you hear it so much.

CV/Gate is damn primitive, but it absolutely destroys midi when it comes to parameter control!

Thanks for the suggestions. I tried cutting the amount of my + / - to half what I needed and although improved the stepping is still very audible. I can understand how the limitations of midi CC cause stepping but rather since some companies had come up with ways to deal with it I had hoped that Kenton might have. Or that the Pro 2000 could accept 14 bit. But again I guess it's more realistic to accept that the companies that have come up with solutions to that tend to be the bigger synth companies and that those kind of solutions would be beyond the capabilities of the engineers of a smaller company like Kenton.

Still disappointing since the Pro 2000 seems to excel in so many areas. In fact, my SEM patch panel doesn't track accurately, and after 5 octaves tends to be about 15-20 cents flat and the scale function has proven to be invaluable to me and has made the tracking of the SEM rock solid and in tune 5 octaves and beyond.

I've asked them also about the improved functions of the Pro Solo - for example, triggering LFOs like an envelope and being able to start the phase of the LFO wave at a chosen point and they've also told me that they have no intentions of adding these functions to the Pro 2000, so for all intents and purposes, even though it's their flagship midi to CV, it's probably safe to say it's done with its lifecycle and all development and pretty much put to rest by Kenton.

I'll have to explore other options maybe for drawing envelopes - something like Silent Way, for example.

A couple potential theoretical solutions. If the Kenton supports 14-bit NRPN => CV mappings then maybe one of your controllers can be told to transmit controll messages as NRPN (do any synths do this? I doubt it, I figure most just send pitch bend as pitch bend, etc.)

The simpler solution would be if they interpolated the data. The problem with this is that you incur latency and a degree of sluggishness depending on the size of the smoothing window. If they take the average over the previous 16ms then you're looking at a 16ms latency before full scale is hit. The smaller the window the tighter it will feel but you'll get more stair stepping.

If you plan to use plugins like midishaper, then I suggest you look at Silentway. It uses audio outputs of your interface to send DC voltages to your analogue gear. It doesnt use MIDI (other than note input) and therefore isn't constrained to 127 steps.

OP I think the problem is the way DAW records pitchbend , or any midi controller (or the way it is sent). rather than the resolution of midi. it seems to have this awful optimisation quantisation thang going on.. and you can't switch it off

I use cubase and have horrible results UNLESS I go into KEY edit and use the drawing tools using the control lane WITH SNAP SET TO OFF

here's what a pitch bend on cubase looks like in KEY EDIT. note: quantise and snap were both set to off for the recording.
so what you're looking for there are the 'steps' - please ignore the dire overall shape of it, which is not the issue, that's just me and my crap pbend skillz...! looks like an old man with parkinsons did it!

here's the same thing, same scale, again with snap off, using the parabola drawing tool instead.
much better. try it:

so record your movements, then use key edit and redraw the lines using the original as a guide. no idea if live can do this but i have no zipper problems in cubase using this method

I think something else is wrong here. I have owned several ProSolo's mk1&2, a Pro 2 and now a Pro 4 and don't have this zipper noise issue??
....

I can't believe everyone has this issue otherwise Kenton would have been out of business years ago!

I sent that audio example over to Kenton with an email and they wrote back telling me that it was normal and it was due to the resolution of midi, and not them because midi is 7 bit. I asked them if they allow 14 bit values for mod wheel and they said no, and they have no plans to update the OS for the pro 2000 to do so.

I haven't made much progress and I am still bummed about this issue. The pro 2000 has a great number of auxes in the back to control stuff, but I can't use midi to send values. Talk about a waste of real estate.

I do like other functions of the pro 2000, which makes this whole thing a shame. I've been thinking of adding an expert sleepers euro module to use silent way to send CV via midi. I wonder if that works better.

Anyone who has the Sem Pro out there can confirm or not if the Oberheim midi to CV suffers from this problem or not?

OP I think the problem is the way DAW records pitchbend , or any midi controller (or the way it is sent). rather than the resolution of midi. it seems to have this awful optimisation quantisation thang going on.. and you can't switch it off

Unfortunately, no. I tried this very solution as well. I use Sonar for my DAW and I tried both re-drawing the curve, as well as using the sine tool to draw perfect sine envelopes on the track and neither one worked. I still experienced the zipper noise.

I also sent the track to various VAs (Acess Virus Classic, Nord stage synth section) and obviously their filters were able to track smoothly with no aliasing, although that might be apples and oranges.

Mind you, I don't seem to experience this with other stuff over midi. I have a Korg EX8000 which may or may not be analog based on what you believe, but the filter section is definitely analog and seems to track sweeps over midi with no problems.

If you plan to use plugins like midishaper, then I suggest you look at Silentway. It uses audio outputs of your interface to send DC voltages to your analogue gear. It doesnt use MIDI (other than note input) and therefore isn't constrained to 127 steps.

Ah, it's nice to hear this works. This was a possible solution I've been thinking about to possibly replace the Kenton with.

As it's too late to cancel my order, I'll have a chance next week to check this out with the same equipment (i.e. patch panel SEM + Pro 2000 MKII).

In the meantime, I've been scouring the net using search terms like "zipper noise" + "pro 2000" etc. and I honestly haven't come up with a lot of results. The low resolution of 7-bit MIDI is a well known problem, but like someone mentioned above, if Kenton products regularly caused the kind of zipper noise demonstrated in your example -- which is by anyone's standards totally unacceptable -- I can't imagine they could have stayed in business this long. Prior to purchasing the Pro 2000, I did some research on places like Muff Wigglers, etc. and it seemed to be a widely used, highly regarded unit. There is no way some of those hardcore modular dudes at Muff's would accept anything like this.

So... what am I trying to say? Well, I guess it's that I find it hard to believe. I'm not doubting you, of course -- especially since you said you sent the file to Kenton and received the response you did (which is pretty shocking). I just find it... hard to accept. It doesn't make sense given everything I've read about the Pro 2000.

Unfortunately, no. I tried this very solution as well. I use Sonar for my DAW and I tried both re-drawing the curve, as well as using the sine tool to draw perfect sine envelopes on the track and neither one worked. I still experienced the zipper noise.

I also sent the track to various VAs (Acess Virus Classic, Nord stage synth section) and obviously their filters were able to track smoothly with no aliasing, although that might be apples and oranges.

Mind you, I don't seem to experience this with other stuff over midi. I have a Korg EX8000 which may or may not be analog based on what you believe, but the filter section is definitely analog and seems to track sweeps over midi with no problems.

I do appreciate the suggestions, though.

Regards,
Frank

Ok i've done a little investigation.. and you're right. i've only really automated my JP8 and my PRO5 through midi and they're fine for zipper.. or they seemed to be when i last used them ( I was happy with the result of my 'high resolution' technique at the time - perhaps i didn't listen carefully enough) i assumed CV gear would be the same as it's all the same midi values EDIT so from what nutjob says below, i'm now guessing that midi->midi works better because it's 14bit, where as the aux CV outs on the kenton are 12bit

I was on my semi modular mono just now, with midi->kenton 2000 -> CV trying different things out. something that really helped is if you narrow the range of of the kenton. for example i used AUX 3 to control filter CV using pitchbend. i changed the min and max values so they were closer and came up with a work around.

the files attached are a self oscillating filter moving through 1 octave using the full range of the pitch bend.

the first is a line drawn on the control lane in key edit with snap on and Q length set to 1/16 to highlight the stepping

the second is the same again with the snap off.

it's not ideal but usable i think. so the technique is: reduce the amount of voltage movement in the kenton to gain higher resolution. basically you're squeezing those 127 values into a smaller space.

PS ionian and maisonvague, i've always found the LFO on my kenton (2000MK1) to be unusable because of the zipp. which is a shame because you can sync that to midi. i wonder if the MK2 has better resolution for the LFO and porta ( i can use the portamento, it does zip but if you set it right it is usable) EDIT but perhaps the LFO is also usable from the main outs, giving a better 14bit resolution

@golden beers Thanks for your investigative efforts! This is encouraging. I will definitely be digging into this next week as soon as the Pro 2000 arrives. I'd really like to not have to send it back.

The whole reason I ended up going with the 2000 over the Solo was that I wanted to be able to control more than one synth and then have all of those extra Aux outputs. I was already prepared for the usual compromises when working with MIDI... but not to the degree demonstrated by ionian's example. Had I known the compromise would be that great, I'd have gone with the cheaper Pro Solo for basic CV/Gate and then looked at something like Silent Way for more aux CV control.

Regarding the resolution of the LFOs, I'm not sure if that's changed in the MKII. I fear not, which means I guess I can expect some zipper noise there, too. I assume though this would mostly be audible with the sine wav, right?

fwiw 12bit is like what, 4096 steps? and 14bit is 16384 i think? versus the 127 on midi? I dunno, i don't know if i could say I agree that it's that. I dunno, sounds like somethings wrong with your pro-2000, i've never heard zipper on mine...

fwiw 12bit is like what, 4096 steps? and 14bit is 16384 i think? versus the 127 on midi? I dunno, i don't know if i could say I agree that it's that. I dunno, sounds like somethings wrong with your pro-2000, i've never heard zipper on mine...

i think its because he has the maximum range settings. it depends on the sound. if you use aux out, with maximum cv range and control the filter cv on a mono synth you will hear stepping, i guarantee it.

By Jove! You're right! I can't believe it! I'm usually diligent about doing my homework prior to purchasing gear, but I blew this one.

Oh, well. It's bound to be useful to me in other ways. I'm going to stop worrying about it now until it actually arrives in the studio and I can test it out with my gear.

I don't think you blew it - it does have its short comings but is there a better stand alone unit? I love silent way though with my interface it really needed external biasing and or boosting which I never solved. Would like to try the dedicated expert sleepers interfaces.

i think its because he has the maximum range settings. it depends on the sound. if you use aux out, with maximum cv range and control the filter cv on a mono synth you will hear stepping, i guarantee it.

i reckon if that's the case, it's not due to the bits, it's due to the software/firmware of the thing not providing a clean curve to the steps. I'll have to try this though to confirm.

i think its because he has the maximum range settings. it depends on the sound. if you use aux out, with maximum cv range and control the filter cv on a mono synth you will hear stepping, i guarantee it.

Ok I'm not in the habit of disagreeing with GB but I have attached a file. This is an MS20 High pass controlled from a Novation SL through a Kenton Pro 4 via the Aux out.

I dont hear anything like the stepping encountered by the OP??

I have tried to open and close the filter fast and slower in case thats the issue. The CV range is at full on the pro4.